Photo credit: Margherita Caprilli for Fondazione IU Rusconi Ghigi

Like many cities around Europe and the world, the City of Bologna is facing complex socio-economic and environmental challenges, including energy management, urban mobility, climate adaptation, and sustainable growth. 

These challenges are highly interconnected and increasingly complex, thus making conventional decision-making processes possibly unfit to respond to today’s issues. Nevertheless, nowadays data is readily available, and digital tools can be leveraged by public administrations to better understand, predict, and steer urban dynamics leveraging the existing amount of raw data that is produced and created every day. 

By leveraging and mastering effectively the capabilities of Artificial Intelligence and automated data analytics, Digital Twins can facilitate public administrations in the transition towards more evidence-based policymaking. This new approach can enable cities to better understand, plan and implement the necessary reforms for the future.

To address these challenges and provide administrators with an effective tool for guiding policy and strategy, the City of Bologna initiated the Bologna Digital Twin project. In its current phase, the digital twin system incorporates a data lake (a repository designed to store and process large amounts of unstructured or structured data), where all relevant raw data from the City of Bologna is being collected and organised. These data will be then analysed and exploited through machine learning techniques and 3D modelling to create a real-time digital replica of the city, enabling the replication, analysis, and prediction of urban dynamics. By merging multiple data sources, the digital twin will continuously offer an updated and more complete view of the city and its complexity.

The Bologna Digital Twin project is publicly funded with an initial investment of EUR 7 million from the National Operational Programme Metropolitan Cities (PON Metro) funds, which are European structural funds allocated to support regional development, among other objectives. Concurrently, the project also relies on Bologna’s High-Performance Computing, Big Data and Quantum Computing Research Centre, one of the five National Centres established by the National Recovery and Resilience Plan (RRP) aimed at supporting the R&D of strategic sectors, including digital society and smart cities.

As part of its wider plan for social, environmental, and technological change, the Digital Twin is considered a crucial tool for Bologna as it is thought to contribute to some of Bologna's most important municipal ambitions including climate neutrality by 2030, better public health and urban spaces and relieve of the housing shortage by building 10,000 new homes over the next decade. The Digital Twin, therefore, is not just a technological project but a strategic policy tool aimed at transforming urban governance through data-enhanced decision-making. In fact, the concept of “digital democracy” is a defining feature of this project, ensuring data-driven governance and enhanced citizen engagement. 

As presented by the project team, the Bologna Digital Twin has three distinctive features:

1. A civic-centric policy tool that fosters data-driven decision making through open data use. The platform is designed to help the administrations to manage data in a democratic way, and to design data-driven policies for the most pressing social issues. 

2. A long-term and collaborative process. The project is the result of a continuous collaboration process that builds on new methodologies (e.g., co-design) and academic research above all. The city also collaborates with international partners, from European cities to US Universities     , to share best practices and lessons.

3. A technology platform for collecting, analysing, integrating, visualising, and simulating urban data to support decision-making. The technology platform is planned to have key features based on 3D modelling and machine learning techniques.       Beginning in 2025, the city will collaborate with the University of Bologna’s      to develop advanced AI tools.

The Digital Twin for the City of Bologna is not only an innovative solution, but the Consortium is also leveraging co-design methodologies for its development. The aim is to ensure that the digital twin aligns both with the administrative needs and citizen expectations, involving them throughout the ongoing development process of the platform. In fact, the stated objective of the project is not only to create a machine-generated data-only urban digital twin, but a Civic Digital Twin, where, in addition to modelling and simulating the physical city in a virtual environment, the tool also accounts for people’s attitudes and choices and human-generated data. As emphasised in the publication “Towards civic digital twins: co-design the citizen-centric future of Bologna” (2024), authored by multiple Consortium partners, stakeholder engagement is key in ensuring that the civic digital twin is citizen-centric. Citizen groups, municipal departments, and academic experts are expected to be involved and engaged with regular workshops. Through this process, various stakeholder groups can provide unique perspectives on their most pressing needs, priorities and expectation. As a result, the digital twin can serve as a policy tool to co-create policy solutions that are adaptable and responsive to evolving and effective urban needs. For instance, in the case of mobility challenges and traffic regulations, the Civic Digital Twin may aid decision-making by showing how regulations affect citizen behaviours, traffic, emissions, and social and economic impacts.

Another key aspect to the Bologna Digital Twin Consortium and administration, according to Ms. Paolazzi, Innovation Officer at the City of Bologna, is the strong focus on the openness and transparency of the overall development process and hence on the utilisation of an existing open data ecosystem. This creates a digital platform where academics, developers and citizens can all see where the data comes from, thus facilitating reuse among the citizenry and across administrations. In fact, the data lake created feeding the digital twin is planned on openness and transparency principles, including:

• Ethical data use by design, adhering to EU privacy regulation and AI regulations from the ideation stage;
• Interoperability and reusability by default, allowing for the potential adoption by other municipalities within the Bologna metropolitan area.

The City of Bologna actively engages in international partnerships as part of the Digital Twin’s development. The city exchanges best practices with European peers through networks like Eurocities and collaborates with global leaders, including institutions in the United States (University of Virginia). Through these collaborations, the municipality of Bologna seeks to incorporate research, learn from other cities' experiences, and contribute to the overall knowledge and discussion about digital twin technologies. Depending on the collaborating city, various topics such as data governance challenges and civic issues like citizenship engagement can be addressed.

As of today, three use cases that were piloted are under development. They highlight the versatile and horizontal potential of the digital twin across multiple strategic and sensible sectors for the urban development of Bologna:  

1. Mobility: the digital twin is intended to assess the impacts of the “30 km/h zone” policy that has been approved by the current city administration, whose goal is to both decrease traffic-related pollution and decrease the number of deadly incidents. The tool will offer an overview of the traffic flows and congestion trends of the city, providing predictive insights as well. Similarly, the tool will inform the city’s public transportation strategy focused on optimising the tram route, minimising disruptions, and benefitting as many citizens as possible.

2. Energy: the tool will allow the urban energy consumption analysis, starting from the city’s building stock data, and therefore support the proposals of sustainable solutions to inefficiencies. The analysis will support the design of policies aimed at optimising energy consumption and thus reducing environmental impact.

3. Urban planning: The digital twin is increasingly identified as a useful tool to improve urban planning tools (e.g. Neighbourhoods Planning) and to support the municipality in managing emergencies (e.g. Garisenda Tower). 

The Bologna Digital Twin offers transformative potential across multiple dimensions:

• Enhanced decision-making. Real-time data and evidence-based simulations provide administrators with precise insights into urban phenomena. For example, traffic congestion can be addressed more effectively by testing various scenarios in a virtual environment before implementing changes in the real world. 

• Digital democracy and citizen engagement. Building on the city’s open data ecosystem and co-design workshops, the administration aims to ensure that the platform is tailored to administrative and citizens’ needs. The (Civic) Digital Twin of Bologna not only supports data-based policymaking, but it also strengthens civic engagement and transparency. The (Civic) Digital Twin enables citizens to access and consult complex urban data in a more user-friendly way. Tools such as interactive dashboards are expected to allow residents to engage with information about mobility patterns, environmental conditions, and urban planning initiatives. This transparency builds trust between the public and administration, while empowering citizens to actively participate in shaping local policies and in co-creating solutions.

• Administrative efficiency and effectiveness. The platform has the potential to increase administrative responsiveness and flexibility. For instance, predictive insights can identify maintenance needs for urban infrastructure before problems arise, reducing downtime and costs, or allow for the optimisation of public transportation according to citizens’ needs. 

Some challenges have already been identified or are foreseen for the short and medium-term future:

• Cooperation complexity among various stakeholders. While successful collaboration strategies are established among Consortium partners and other stakeholders, including municipal departments, research institutions, and technology providers, it is recognised that further synergies and coordination will be essential for the continued success of the Digital Twin implementation and full operationalisation. Clear communication and stakeholder identification strategies will be necessary to address this challenge in the future. 

• Sustainability of the project across time. Digital Twins projects can last more than 20 years to be fully implemented, scaled and operative, and it is fundamental to make the tool sustainable and adaptable across administration cycles and to changing policy and political priorities. 

• Skill gaps across the public administration. Public administrations like the City of Bologna can lack the in-house capabilities to adopt such technologies and have to rely on external actors. In this case, Bologna decided to collaborate with other research-based public and private institutions. In the future, training, recruiting and retaining digital talent remains a pressing concern for the administration.

• Scalability. Transitioning from a prototype to a fully operational system by 2026 is a complex process. Ensuring that the platform can handle increasing amounts of data and support broader applications—including potential use by neighbouring municipalities—requires a scalable design. Additionally, maintaining interoperability with other systems and adhering to European standards will be crucial for the platform’s long-term success.

Useful links:

• Presentation of the Digital Twin project
• Towards Civic Digital Twins: Co-design the citizen-centric future of Bologna

Project contacts: 
Stefania Paolazzi, Innovation Officer at the City of Bologna (stefania.paolazzi@comune.bologna.it)
Marco Pistore, Head of Research Unit – Modeling and Simulation of Socio-Technical Systems at Fondazione Bruno Kessler (pistore@fbk.eu)